1. Field of the Invention
The present invention relates to a liquid crystal display and a thin film transistor array panel.
2. Description of the Related Art
A liquid crystal display (LCD) is a common type of flat panel display. An LCD includes two panels provided with field-generating electrodes, and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer, which changes orientations of LC molecules in the LC layer to adjust polarization of incident light.
A disadvantage of the LCD is that it has a relatively narrow viewing angle. Various techniques for enlarging the viewing angle have been suggested, such as utilizing a vertically aligned LC and providing cutouts or protrusions at field-generating electrodes such as pixel electrodes and a common electrode.
For example, when the pixel electrodes and a common electrode respectively have cutouts, the cutouts induce a slanted electric field, and the slanted electric field controls falling directions of liquid crystals. Control of the falling direction of liquid crystals makes it possible to widen the viewing angle of liquid crystal display.
For example, when the pixel electrodes and the common electrode respectively have protrusions, the protrusions are formed on both of pixel electrodes and a common electrode, the protrusions induce a slanted electric field, and the slanted electric field controls falling directions of liquid crystals.
Additional methods in which pixel electrodes have cutouts and protrusions formed on a common electrode may be used to control falling directions of liquid crystals.
An LCD using cutouts or protrusions has a viewing angle of greater than approximately 80 degrees in any direction, which has an improved contrast ratio in view of a standard contrast ratio of 1:10, and in view of gray scale inversion where a viewing angle of occurring brightness inversion is a standard angle. However, such an LCD shows poor visibility that is inferior to a twisted nematic mode LCD. The poor visibility is caused by discordance of the gamma curve between the front view and lateral view.
For example, in a vertically aligned mode LCD using cutouts, as the viewing angle increases, the picture plane becomes brighter and the color shifts toward white. When this phenomenon is excessive, the image distorts because the brightness difference between gray scales disappears.